Tis the season. All these cars, esp ones that are outside all the time where leaves exist, need the rubber drain tube(on the firewall center) clipped about 2cms to allow what becomes the inevitable compost plug of leaves and twigs to clear. Remove the tube, and clean it and the debris in the aquarium. Advanced cases may require a hose to ensure everything is flushed. This will help avoid smells, leaks and heater fan resistor and wiring problems.